Telephone system



Nov. 30, 1937. R. HOEFERT ET AL 2,100,510

TELEPHCNE SYSTEM Filed May 7, 1936 2 Sheets-Sheet 1 F/G.3 I 54321 I r -1NVENTOR5 Rem/10m HOEFERT BY R7 M/aLLACK ATTORNEY. v

Patented Nov. 30, 1937 UNITED STATES 2,100,510 TELEPHONE SYSTEM Reinhold Hoefert,

Wollack, Berlin,

Berlin-Gatow, Germany, assignors to Sie-' and Kurt mens & Halske Aktiengesellschaft, Siemensstadt near Berlin, Germany, a corporation of Germany ApplicationMay 7, 1930, Serial No. 78,396

In Germany May 10, I935 18 Claims. (01. 179 '1s) The invention relates to a circuit arrangement for automatically operated telephone systems which are exposed to considerable violent shocks or other disturbances.

In such systems, for example on warships in which resilient. mounting of the devices ,(frames, selectors and relays) does not suflice to maintain the connecting devices in the position taken up when a call is proceeding, release of the connection can take place on the occurence of a considerable shock and thus the calling subscriber has to set up the connecting path once more.

Also in such systems the selectors set by impulses cannot be used since shocks occuring during dialling result in false connections. This disadvantage is obviated according to the invention in that after the connection has been released by the mechanical influencing (for example by a shock) of the switching devices (relays), which take up a particular position (working or rest position) while a call is in progress; switching means become automatically operative which cause a reestablishment of the connection between the two previously connected subscribers.

5 The invention also aims at setting the selector switch on the desired connecting line efliciently while dispensing with the necessity for transmitting impulses for the purpose of setting the selector, this being achieved in a simple and practical manner in that a relay group in the exchange is influenced from a calling subscribers station over characterizing lines, this relay group characterizing the contact set of the desired subscribers station at a selector serving to set up the connection which is at the disposal of a calling station.

An embodiment of the invention is represented in Figs. 1 and 2 of the attached drawings. This represents a system in which on initiating a call, selectors seek out the calling subscribers line and a further selector is set on the desired subscribers line by means of the application of potential (caused by the calling subscriber) to the desired connection. Fig. 3 is a modification of the call initiating means on a line.

The individual switching operations for establishing a call, for example between subscriber N, Fig. 1, and subscriber NI in Fig. 2 are as follows:

When the subscriber N takes up his receiver the following circuit is closed: negative, winding I of relay R, contact 8t, lead 9, over the loop of the subscribers station N, contact Hit and positive. Relay R energizes and closes contacts I I r and I21". The calling subscriber is characterized at wiper d of the call finder AS2 by contact Hr. By the closing of contacts I27 c l w s .1 $9

- net DASI, and negative.

rupter RU, contacts I91),

up: positive, contact I21, I313, My, relay R2, thermo-relay Th and negative. Contacts I512, I612 and H12 are closed by relay R2. The testing circuit over wiper d is, prepared by contact, I112. The following circuit is established for the rotary ,5. magnet DASI by contact I 5r2 positive, relay interrupter RU, contacts I Bpand I5r2, rotary mag Over contact-W172, the following circuit is closed: positive, relay inter- DAS2 and negative. By means of the relay interrupter RU the driving magnets ,DASI and -DAS2] are operated simultaneously and thus the call finders ASI and AS2 are advanced simultaneously. The simultaneous stepping. of the two call finders l5 continues until the testing circuit is established 1 over wiper d of call finder ASZ. The, testing circuit passes over: positive, contactsZOoand' I'Ir2, windings II and I of relay P, contact 2 I z, wiperd of call finder ASZ, contact I. Ir, winding II of relay .20

R, contact 221', winding I of relay-T and negative. 4

.In the above circuit relay T energizes and opens contacts 8t-and Hit. The calling circuit over winding I of relay Ris thus broken. Relay R locks up over its winding II in the testing circuit. 25

Relay T at contact I3t breaks the circuit for relay R2 and the thermo-relay Rh. If for "any reason the testing circuit over wiper d of the call finder A82 is not established in a given'time the ;thermo-relay Th energizes and closes contact 30 -33th. Thus the call impulse given by contact 121 a is transmitted to the lead 34 which leads a second call finder group.

- In. the testing circuit relay'P is energized and by opening-contacts I81) and 19p brings the call 35 finders ASIand ASZ to rest. Relay P closes'contacts 23p to 29p. Switching throughv of the speaking line takes place over contacts 23p and 24p so that the feeding-bridge-relayis energized over: negative, winding I of relay I, winding I of 4.0

, relay A, contact-23p,wiper a, of call finder ASI,

lead 7, over the loop at the subscribers station N, lead I, wiper bof call finder ASI, contact 24p, winding II of relay-A, winding II of relay Iand positive.

Relay I does not energize'in the feeding circuit sinceit is arranged as a differential relay. Relay A effects the short-circuiting of winding II of relay P over contacts 30a and 3Ip so that the calling subscribers-line is guarded in the known 50 manner. Relay V is energized over: positive contact 32a, relay V and negative. 7

By the closing of contacts 25p to 29p the characterizing relaysII to XI are brought under the influcncc of the calling station. 55

I6r2,'rotary magnet 10' In the embodiment described two selectors AS are used for setting on a calling line. One selector may, however, be used just as well, this selector possessing the same number of wipers as the other two selectors together.

If the, calling subscriber w1shes to converse with the subscriber connected to contact I of the selector D3, positive potential must be applied to the fixed contact I of wiper e of the switch D3. For this purpose it is necessary for the contacts 351, 3611, 3IVI, 38VIII and 39Xfto be closed. Accordingly the relays I, II,.VI, VIII and XI must be energized. This may be achieved in the embodiment in Fig. 1 by the calling subscriber N operating the keys Tl, T2, T3, T4 and T5. The keys TI to T5 are looking keys which remain operated until the subscriber replaces his receiver. By operating key TI positive potential is applied to the lead I so that the differential relay I occurring in the feeding circuit is energized. By operating the key T2 a circuit is set up over: positive, T2, lead 2, wiper c of call finder ASI, contact 25p, relays II, III and IV and negative. By means of T3 the circuit over: positive, key T3, lead 3, wiper d of call finder ASI, contact 26p, relays V and VI and negative, is closed. Key T4 causes a circuit for relays VII and VIII to be set up. The circuit passes over positive, key T4, lead 4, wiper a of call finder A82, contact 21p, relays VII and VIII and negative. Over the circuit: positive, key T5, lead 5, wiper b of call finder AS2, contact 28p, relays X and XI and negative, the relays IX, X, XI are energized. Thus all the characterizing relays I to XI are operated. This merely causes the characterizing of the subscriber connected to contact I of the switch D3 by relays I, II, VI, VIII and XI over contacts 351, 36II, 3'IVI, 38VIII and 39XI. The connection of potential to another contact cannot be effected by the additional energization of the other relays III, IV, V, VII, IX, and X.

According to the embodiment it is necessary before taking up the receiver at the calling station to first depress the characterizing keys TI to T5 so that the characterizing relays are energized directly after the setting of the call finders ASI and A52 on the calling subscribers line. When after the switching through of the line at the contacts 23p and 24p the feeding-bridge relay A also energizes the circuit for the rotary magnet DM3 of the switch D3 is closed over: positive, relay interrupter RU, contacts 59c, 40112 and Ma, rotary magnet DM3 and negative. The wipers of the switch D3 are advanced until the wiper e reaches the contact indicated by the characterizing relays I-XI. In the present case the switch D3 has only taken one step before reaching the contact to which the desired subscriber is connected. The characterizing circuit over wiper e passes over: negative, relay C, contact 42a, wiper e in position I, contacts 391K, 38VII-I, 3IVI, 3511, 351 and positive. Contact 59a is opened by relay C and the switch D3 is just brought to rest. Relay P2 is energized over-z positive, windings I and II of relay P2, contact 43c, wiper c of the switch D3, winding II of relay RI, windings II and I of relay TIII, and negative. The disconnection of the calling circuit for the desired subscriber NI is cut oif by relay TIII in a manner which is not represented.

By closing contact Mp2, winding I of relay P2 is "short-circuited and thus the desired subscriber is guarded in the known manner.- By the closing of 'con-tacts 45102 and 46 12 the speaking line is switched through. A circuit is established for the direct current bell over negative, slow interrupter LU, resistance W, contacts 41 02 and 48g, wiper d of the switch D3, bell Wk: and positive. When the called subscriber NI replies by taking up his receiver, the following feeding circuit is established: negative, winding I of relay Y, contact 45p2, wiper a, of switch D3, contact 49XV, over the loop of the subscribers station NI, contact EOXV, wiper b of the switch D3, contact 46102, winding II of relay Y and positive. Relay Y at contact 48y breaks the circuit for the direct current bell Wk. Relay Y is kept up independently of the called subscriber over: positive, contacts Slp, 52y, winding III of relay Y and negative.

7 If the desired subscriber is engaged, relay P2 cannot energize. The busy signal is applied over contacts 536, 54c and 55122 to winding III of relay Y. The busy signal is transmitted inductively to windings I and II in the speaking path so that the calling subscriber can perceive the busy signal. Moreover, the following circuit is closed: positive, interrupter LU, resistance W, contact 56 12, winding II of the choke-coil Dr, contacts 510 and 58c and positive. An intermittent signal is produced which is transmitted inductively to the winding I of the choke-coil Dr, so that the desired subscriber who is engaged is also informed of the presence of a call. 7

If the feeding bridge relay A is energized after the setting of the selectors ASI/ASZ and relay C does not energize over wiper e of the selector D3 within a given time, relay TM is energized. The circuit passes over: positive, contacts 60a, file, 622, thermo-relay Thl and negative. The thermo-relay Thl opens contact 63thl and closes contact 64ml. Relay Z energizes over positive, contact 64ml, relay Z, resistance W2 and negative. Relay Z locks up independently of contact 64ml over contact 65.2. At contact 2Iz, relay Z opens the testing circuit over wiper d of the selector AS2. Relay P and with it relays A, V and the characterizing relays IXI' release. Since the testing circuit over Wiper d of the call finder A82 is broken, the subscribers relay T releases. Relay R locks up in the calling circuit. By means of the thermo-relay ThI the circuit for relay Z and thus the break at contact 2Iz is maintained until relay Th has caused switching over on to another call finder group at contact 33th, over: positive, contacts l2r, I3t, My, relay R2, relay Th and negative. switching over takes place, contact 64ml is open and contact 63th! closed, so that relay Z releases. Thus, the devices of the first set of equipment which has been taken into use are released. Since the calling condition and the characterizing condition of the calling station are still in existence, a connection is established in the same way over a further equipment set in the same way as was described for the equipment shown in the drawings. 7

If the subscriber reached over selector D3 is engaged and the calling subscriber is a specially privileged subscriber who is provided with the key T6, then this privileged station can switch on to the existing connection.

By operating the key T6, the circuit over positive, key T6, lead 6, wiper c of the switch AS2, contacts 29p, relays L and E and negative is closed. Relay E opens contact 66c and closes contacts 51c and 68e. The calling subscriber is thus connected with the desired subscriber independently of the energizing of the testing relay P2 over contacts file/65102 and Bile/10112. By the opening of contacts 53c and 582, the engaged signal for the calling subscriber and the tick When this I ing signal for the called subscriber are disconnected. The privileged subscriber can also set diflerent ringing independently of the interrupter LU. In the circuit which is closed by the key T6, relay L occurs. Relay L closes a ringing circuit independent of contact 48y and p2 over negative, resistance WI, contact HZ, wiper d of selector D3, bell Wk and positive.

A subscriber is also in the position to connect together all the subscribers of a system in a conference call. For this purpose the calling subscriber according to the embodiment, merely depresses the key T2 and takes up his receiver. After switches ASI and A82 have been set in the manner already described, the relays II, III and IV energize by the operation of the key T2. On account of the operation of these relays, contact 3! of the selector D3, is characterized by the opening of contact 1211 and the closing of contact 1311. The characterizing circuit over wiper c of the switch D3 passes over negative, relay C, contact 42a, wiper e of selector D3 in position 3|, contacts 13H, 74V, IBVII, TIIX, HI and positive. The selector D3 is advanced to contact 3! and is then brought to rest in the manner previously described. Over wiper c and contact 3| the following circuit is closed; positive, windings I and II of relay P2, contact 430, wiper c of the selector D3 in position 3|, relay XV and negative. In the circuit just mentioned relay P2 energizes and effects the switching operations already described. Relay XV opens contacts 49XV and 50XV and closes contacts 'IHXV and XV. The subscribers line of the station NI is switched over on to the common line connected to contact 3|. Contact BIXV closes the ringing circuit. Relay XV in the same way as for the subscriber NI represented, causes the switching over of the lines of all the subscribers and the ringing circuit on to the line connected to contact 3| of the selector D3, so that all the subscribers are called and are connected to the common line connected to contact3l. The called subscribers reply so that the calling party knows which of the subscribers are taking part in the conference call.

The release of a call is brought about in the following manner: When the subscriber N replaces his receiver, the feeding bridgerelay A releases. Relay A opens the testing circuit over relay P and wiper d of selector AS2. Relay P releases. At contact 32a relay A breaks the circuit for relay V so that this relay also returns its contact to normal. At contact 42a, the circuit for relay C is broken and this releases and by opening contact 43c, breaks the circuit for relay P2. Relay P2 opens contacts 45112 and 46122 so that the line is disconnected and the feeding bridge relay Y is caused to deenergize. By the opening of contact 430, the relays reached in the testing circuit over wiper c of selector D3 (for example RI, Tl!) or XV) are released. By the interruption of the testing circuit of switch AS2 over wiper d at contact 3%, the subscribers" on account of shock, the position occupied by a relay is altered and thus release of the call is brought about, then according to the present arrangement, the connecting path established over the selectors is immediatelyre-established after the'shock." r r e If, for example, the armature of relay A is returned to its normal position by means of. a shock, the operated contacts of relay A'are also opened, and the circuit for relay P'is broken at contact 30a; Relay P returns its contacts to normal. subscriber still exists over the characterizing 'keys Tl.T5-and the calling, circuit for the callingstation is again re-established after the inter- If on account of a shock, only the armature.

of relay P is returned to the rest position, relay A is deenergized by the opening of contacts 23p and 24p. Release takes place in the manher already described. 'On'account of there-- ceiver being still removed from its positionfand.

since the characterizing condition for the desired subscriber still'exists, the connecting path is immediately re-established. While a call is in progress, the contactsof relay Z arein the rest position. If, on account of shock, the armature of relay Z is brought into the working position; the circuit for relay Pis broken at contact 2L2 and the'circuit-for relay A is broken at contacts 23p-and 24p. Release of the call again takes place, the call being subsequently re-established without the'calling subscriber having to execute, any special switching operation.

Since the characterizing of the desired According to the embodiment in Fig. 1 a subscriber is provided with a series of five keys, T|T5 for characterizing the desired subscriber, these keys operatingon eleven characterizing relays for characterizing 3| subscribers stations. In order to simplify the mode of operation at the calling subscribers station, a rotary switch can'be arranged in place of the keys Tl-'I 5 as, for example, is shown in Fig. 3. This rotary switch possesses as many contact positions as there are subscribers stations to be reached, and on setting the rotary switch on a particular contact, positive potential is applied to the various characterizing leads according to the wiring of the leads l5. If a calling subscriber wishes Over the lead connected to contact I of the rotary switch, positive potential isapplied to the leads 1, 2, 3, 4, and 5, sothat the characterizing relays which are reached over these leads are op-' erated. Thus the subscriber, instead of having to operate five keys, has only to setthe rotary switch on contact I.

' 'Which of the keys according to the embodiment shown in Fig. 1 are to be depressed for characterizing the various subscribers may be seen from the pyramidal arrangement of the conneoting contacts connected to Wiper e of the selector D3. For example in order to characterize the subscriber connected to contact Edit is to be closed. Thus the relays I, II, VIII and XI must be energized. 'Ifhis is effected by depressing the keys T1, T2, T4 and T5. If the subscriber connected to contact I3 is wanted then in order to characterize this subscriber the contacts 351, 84VII and 851K must be closed. Relays I, VII and IX have to be energized. This is effected by depressing keys Tl, T4 and T5. If the subscriber who is connected to contact 23 is wanted the contacts BBIX and 81111 have to be closed, for this purpose relays IX and Ill must be energized. This is effected by depressing keys T2 and T5.

What is claimed is:

1. In 'an automatic telephone system, .sub-

I scriber controlled switching means for setting up connections between subscribers in the system, and means for automatically resetting an established connection in case it is interrupted.

2. In an automatic telephone system, automatic switching means, means controlled by any subscriber in the system for operating said switching means to establish a connection with any other subscriber, means controlled by said connected subscribers for releasing said switching means and disconnecting said established connection, and means for automatically reestablishing said connection in case said switching means are released other than by the connected subscribers.

3. In an automatic telephone system, automatic switching means, subscriber controlled means for operating said switching means to establish a connection with another subscriber, said switching means remaining operated for the duration of the connection, and means in case said switching means is inadvertently released and the established connection is disconnected for automatically reestablishing said connection independent of any control by the subscriber.

4. In an automatic telephone system, automatic switching means, means controlled by a calling subscriber for initiating the operation of said automatic switching means to establish a telephone connection with a called subscriber, means controlled by said connected subscribers for releasing said switching means responsive to the termination of the call, and means for automatically reoperating said switching means to reestablish the connection between the said subscribers in case the release of said switching means occurs inadvertently and without control by the subscribers.

5. In a telephone system, a plurality of subscribers lines, a group of relays, automatic switching means, means controlled by a calling line for operating a particular combination of said group of relays in accordance with the line .of a called subscriber, said automatic switching means operated in accordance with said combination of relays to establish a connection between the calling and called lines, said automatic switching means and said relays subject to violent shock and thereby released whereby said established connection is released, and means for automatically reoperating said switching means and said relays to reestablish the connection.

6. In a telephone system as claimed in claim 5 in which certain relays in the automatic switching means are released when subjected to violent shock and the established connection released, and in which the said relays are reoperated to again establish the connection with the called line due to the particular calling combination of relays being again operated automatically without control by the calling subscriber.

'7. In a telephone system, subscribers lines, a: group of relays, a set of keys at each subscribers line, said keys operated by a subscriber in certain combinations in accordance with 2. called subscribers line to effect the operation of certain ones of said group of relays, automatic switching means controlled by the operated ones of said group of relays to establish a connection with the desired called subscribers line, said automatic switching means and relays subject to violent shock whereby they are released and said connection disconnected, said operated keys again operating said combination of relays to their operated condition, and means for reoperating said automatic switching means in accordance with the operated combination of relays to reestablish the connection with the called line.

8. In an automatic telephone system wherein the switching apparatus is subject to the influence of violent shock, means controlled bya callingsubscriber for characterizing the line of a called subscriber and for maintaining said characterization intact for the duration of the call andat the time of any violent shock, said switching apparatus automatically operated by said characterization to establish a connection with the called subscribers line, said switching apparatus released and said connection thereby disconnected responsive' to the occurrence of a violent shock, and means whereby said switching apparatus automatically 'reoperates and again establishes the connection under influence of the operated characterizing means.

9. In an automatic telephone system, subscribers lines, a relay group, characterizing leads extending from said subscribers lines to said relay group, means controlled by a calling subscriber for operating certain combinations of said relays over certain combinations of said characterizing leads, said combinations of operated relays corresponding to a particular called subscribers line, and automatic switching means operated in accordance with the operated combination of said relays to establish the connection with the called and calling subscribers lines.

10. In an automatic telephone system, subscribers lines, a finder switch for finding a calling line, a second finder switch for finding the called line, and means controlled by the subscriber of a calling line for marking the calling line in the bank of the first finder, for marking the called line in the bank of the second finder, and for initiating the operation of both of said finders to find the marked lines.

11. In an automatic telephone system, subscribers stations, a relay group, a plurality of characterizing leads extending from said stations, means controlled at a calling subscribers station for energizing combinations of said characterizing leads in accordance with a called subscribers station, means for associating said -characterizing leads with said relay group to operate combinations of said relays in accordance with the ener gized characterizing leads, an automatic switch, said combinations of relays marking the called station in the bank of said switch, and means for operating said switch to connect the calling and called stations.

12. In an automatic telephone system as claimed in claim 11 in which the relay group is common to all the subscribers stations and the number of characterizing leads extending from each station is less than the number of stations that are selectable.

13. In an automatic telephone system, subscribers stations, characterizing leads extending from each station, a relay group, a finder switch for connecting a calling stations characterizing leads with said relay group, means at the calling station for energizing combinations of said characterizing leads in accordance with a called stations number to operate corresponding combinations of said group of relays, a second finder switch having access to called station lines, said operated combinations of relays marking the called stations line in the bank of the second finder switch, and means responsive to the operae tion of both of said finder switches for establishing a connection between the calling and called stations.

14. In an automatic telephone system according to claim 13 in which one of the characterizing leads includes the speaking lead of the call ing station and the same potential is applied to the particular combinations of the characterizing leads.

15. In an automatic telephone system according to claim 13 in which one of the characterizing leads includes a speaking lead of the calling station, one of said group of relays being included in the speaking lead and furnishing speaking current to the calling station. 7

'necting the calling station line with a busy called 16. In an automatic telephone system as, claimed in claim 13 in which responsive to the tions are enabled to operate special relays of the group over a special characterizing lead, and means controlled by said special relay for conline. a

18. In an, automatic telephone system as claimed in claim 13 in which the means at the calling station for energizing the characterizing leads comprises a locking key connected to each characterizing lead, said keys being released from their operated position by replacement of the receiver on the switchhook of the calling station.

REINHOLD HOEFERT. KURT WOLLACK. 

